1. Field of the Invention
The present invention relates to an engine for a vehicle, and more particularly to an engine for a vehicle having an oil supply system which is provided with an oil pan, an oil filter, an oil cooler and the like.
2. Prior Art
In this kind of engine for the vehicle, as described in Japanese Unexamined Patent Publication No. 1-211609, an oil filter is generally arranged in the middle of an oil supply path from an oil pump to a plurality of lubrication positions, and an oil cooler is arranged as occasion demands.
FIG. 8 is a front elevational view of an engine for a motor cycle showing an example of a prior art. An oil pan 103 is attached to a lower surface of a crank case 100, and an oil filter 104 and an oil cooler 105 are attached to a front face of a lower portion of the crank case 100 so as to be arranged side to side and to form a forward protruding shape. Further, there is a prior art in which the oil filter is attached to a lower surface of the oil pan attached to the lower surface of the crank case so as to form a downward protruding shape.
In the engine for the motor cycle, an exhaust pipe is generally arranged so as to extend rearward from a front side of the engine through a lower side of the engine. Particularly, as shown in FIG. 8, in a 4-cylinder engine in which four cylinders are arranged in a orthogonal direction (right and left direction) to a forward moving direction of the vehicle, four exhaust pipes 110 pass through a front side of the engine. Since most of the oil filter 104 and the oil cooler 105 are covered by these four exhaust pipes 110 from the front side, the exhaust pipes 110 form an obstacle when replacing the oil filter 104 and the oil cooler 105, and thus, an inordinate amount of work is involved with attaching and detaching the same.
In order to easily execute the work of replacing the oil filter 104 and the oil cooler 105 from the front side, it is necessary to pipe the exhaust pipe 110 in the front side of the engine so as to bypass the oil filter 104 and the oil cooler 105 in a front view. However, in the structure mentioned above, a length of an exhaust path becomes longer than necessary and the shape and layout of the exhaust pipe 110 are complicated, so that manufacturing of the exhaust pipe is difficult. Further, the lengths of the exhaust pipes are not approximately uniform.
Further, as shown in FIG. 8, in the structure in which both the oil filter 104 and the oil cooler 105 are attached to the front face of the crank case 100, it is necessary to form both a mounting portion for the oil filter 104 and a mounting portion for the oil cooler 105 in the crank case 100 itself. Further, it is necessary to form the oil passage communicating between the oil filter 104 and the oil cooler 105 in accordance with a die casting or the like, and manufacturing the crank case 100 is difficult.